1. Field of the Invention
The present invention relates to a voltage source having a circuit for controlling the output impedance thereof, and more particularly, to a voltage source having a current feedback control loop for source impedance control.
2. Description of the Prior Art
In conventional voltage source amplifiers (VSAs), the source impedance is generally a given function of the open loop source impedance and gain of the voltage control loops (if any are used). As a result, the source impedance is a function of criteria unrelated to the required source impedance. Also, since some loads connected to the VSA output assume a certain source impedance, it has heretofore been difficult to match the output impedance of the VSA to the input impedance of a load connected to the VSA. Full-wave diode bridge capacitive filtered rectifiers are representative of such loads and generally have a source impedance which is less than one percent of the full load of the VSA. Thus, the input current to such rectifiers typically has a characteristic high peak. When this peak current is multiplied by the corresponding peak output voltage of the VSA, a high peak power output results. This high peak power output imposes a stringent specification on the voltage source peak power handling capability and is generally costly to implement.
Accordingly, it is desired to overcome the above-mentioned problems of the prior art by designing a voltage source amplifier which enables the source impedance to be adjusted and/or reshaped such that it is optimal for the corresponding load. The present invention has been designed to provide such capabilities.